This paper proposes a noninvasive method for evaluating the state of a fractured bone using time-series analysis based on speckle interferometry. The fine speckle fringes generated at the fractured section are detected using a gradient-based method and a new evaluation index is contributed for monitoring the state of the fractured bone. A performance test using a test phantom and numerical analysis using a particle method reveal that there is a detectable difference in the proposed evaluation index between cases with and without a cutting plane in an internal object.